dt-bindings: display/msm: dsi-controller-main: Document qcom, master-dsi and qcom, sync-dual-dsi

This fixes warning:
  sm8250-xiaomi-elish-csot.dtb: dsi@ae94000: Unevaluated properties are not allowed ('qcom,master-dsi', 'qcom,sync-dual-dsi' were unexpected)

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Jianhua Lu <lujianhua000@gmail.com>
Fixes: 4dbe55c9 ("dt-bindings: msm: dsi: add yaml schemas for DSI bindings")
Reviewed-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
Patchwork: https://patchwork.freedesktop.org/patch/534306/
Link: https://lore.kernel.org/r/20230427122132.24840-1-lujianhua000@gmail.com


Signed-off-by: Abhinav Kumar <quic_abhinavk@quicinc.com>